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/*
* Copyright (c) 2011 Aeroflex Gaisler
*
* BSD license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef _LINUX_JIFFIES_H
#define _LINUX_JIFFIES_H
#include <asm-leon/types.h>
#include <asm-leon/clock.h>
#include <asm-leon/linkage.h>
/* Suppose we want to devide two numbers NOM and DEN: NOM/DEN, the we can
* improve accuracy by shifting LSH bits, hence calculating:
* (NOM << LSH) / DEN
* This however means trouble for large NOM, because (NOM << LSH) may no
* longer fit in 32 bits. The following way of calculating this gives us
* some slack, under the following conditions:
* - (NOM / DEN) fits in (32 - LSH) bits.
* - (NOM % DEN) fits in (32 - LSH) bits.
*/
#define SH_DIV(NOM,DEN,LSH) ( ((NOM / DEN) << LSH) \
+ (((NOM % DEN) << LSH) + DEN / 2) / DEN)
/* TICK_NSEC is the time between ticks in nsec assuming real ACTHZ */
#define TICK_NSEC (SH_DIV (1000000UL * 1000, (HZ<<8), 8))
/*
* The 64-bit value is not volatile - you MUST NOT read it
* without sampling the sequence number in xtime_lock.
*/
extern u64 jiffies_64;
extern struct timespec xtime __attribute__ ((aligned (16)));
#define jiffies (*((unsigned long *)(((unsigned long)(&jiffies_64))+4)))
/*
* These inlines deal with timer wrapping correctly. You are
* strongly encouraged to use them
* 1. Because people otherwise forget
* 2. Because if the timer wrap changes in future you won't have to
* alter your driver code.
*
* time_after(a,b) returns true if the time a is after time b.
*
* Do this with "<0" and ">=0" to only test the sign of the result. A
* good compiler would generate better code (and a really good compiler
* wouldn't care). Gcc is currently neither.
*/
#define time_after(a,b) \
(typecheck(unsigned long, a) && \
typecheck(unsigned long, b) && \
((long)(b) - (long)(a) < 0))
#define time_before(a,b) time_after(b,a)
#define time_after_eq(a,b) \
(typecheck(unsigned long, a) && \
typecheck(unsigned long, b) && \
((long)(a) - (long)(b) >= 0))
#define time_before_eq(a,b) time_after_eq(b,a)
/*
* Have the 32 bit jiffies value wrap 5 minutes after boot
* so jiffies wrap bugs show up earlier.
*/
#define INITIAL_JIFFIES ((unsigned long)(unsigned int) (-300*HZ))
static inline void
set_normalized_timespec (struct timespec *ts, time_t sec, long nsec)
{
while (nsec > NSEC_PER_SEC)
{
nsec -= NSEC_PER_SEC;
++sec;
}
while (nsec < 0)
{
nsec += NSEC_PER_SEC;
--sec;
}
ts->tv_sec = sec;
ts->tv_nsec = nsec;
}
#endif
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